Power control device for a signal with optimized input dynamics

Abstract

A signal power control device comprises two amplification channels. A first amplification channel comprises a first transconductance amplifier and a second amplification channel comprises an attenuator mounted in series with a second transconductance amplifier. Gain adjustment means allow the respective gains of the first and the second amplifier to be controlled independently, according to laws, ensuring optimum output dynamics across the entire gain range of the power control device.

1. A signal power control device, comprising:
 a first amplification channel comprising a first amplifier, 
 a second amplification channel comprising a fixed-gain attenuator in series with a second amplifier, 
 an adder, and 
 an analog gain adjustment means applied to the first amplification channel and the second amplification channel, an input signal being applied to the first amplification channel, and in parallel with the second amplification channel, the outputs of the first and second amplification channels being connected to the inputs of the adder, and the gain adjustment means being suitable for distributing the respective gains of the first amplification channel and the second amplification channel depending on the power of the input signal according to a distribution law, according to which the gain of the second amplification channel is minimal for the lowest input powers, and the gain of the first amplifier channel is minimal for the highest input powers, the gains of the first amplification channel and the second amplification channel being adjusted in a progressive and continuous manner for the intermediate input powers. 
 
     
     
       2. The signal power control device according to  claim 1 , wherein the first amplifier and the second amplifier are transconductance amplifiers, the gain adjustment means comprising means for controlling a first polarization current I 1  of the first amplifier, and a second polarization current I 2  of the second amplifier depending on a control current I C . 
     
     
       3. The signal power control device according to  claim 2 , wherein the gain of the signal power control device expressed in decibels, is proportional to the logarithm of the control current I C  in the normal operating range. 
     
     
       4. The signal power control device according to  claim 3 , wherein the means for controlling the first polarization current I 1  of the first amplifier, and the second current I 2  are suitable for shaping the two currents, each according to a law dependent on a control current I c . 
     
     
       5. A satellite geopositioning device, comprising a signal reception and amplification channel, comprising a signal power control device according to  claim 1 . 
     
     
       6. A method of controlling signal power, comprising:
 applying an input signal to a first amplification channel and to a second amplification channel in parallel with the first amplification channel; 
 adjusting respective gains of the first amplification channel and the second amplification channel based on the input signal power according to a distribution law, the gain of the second amplification channel being minimal for the lowest input signal power, the gain of the first amplification channel being minimal for the highest input signal power, and the gains of the first amplification channel and the second amplification channel being adjusted by analog adjustment in a progressive and continuous manner or intermediate input signal powers; and 
 adding outputs of the first amplification channel and the second amplification channel. 
 
     
     
       7. The method according to  claim 6 , wherein the adjusting includes controlling a first polarization current of a first amplifier in the first amplification channel and controlling a second polarization current of a second amplifier in the second amplification channel based on a control current.